What is 'Yokoso boku desu'?(Yokoso boku desu 4)

This is the 4th music and animation series titled “Yokoso boku desu” (Welcome it’s me). This series consists of three songs. “Let’s Coritsu”(Be isolated), a song wising for an isolated situation to be connected, “Yoko is Naive”, a song by a mysteriyous woman who has been waiting for something for a long time, and “Kosokoso Bokudesu”, where an earthworm boy, a senior guy, and others extend their own necks. Through these three songs, what do you see in Yokoso Bokudesu?